Measuring and Controlling Energy Spread in CEBAF
As compared to the electron storage rings, one advantage of recirculating linacs is that the beam properties at a target are no longer dominated by the equilibrium between quantum radiative diffusion and radiation damping because new beam is continually injected into the accelerator. This allows the energy spread from a CEBAF-type machine to be relatively small; the measured energy spread from CEBAF at 4 GeV is less than 100 parts per million accumulated over times of order several days. In this paper, the various subsystems contributing to the energy spread of a CEBAF-type accelerators are reviewed, as well as the machine diagnostics and controls that are used in CEBAF to ensure that a small energy spread is provided during routine running. Examples of relevant developments are (1) stable short bunches emerging from the injector, (2) precision timing and phasing of the linacs with respect to the centroid of the beam bunches on all passes, (3) implementing 2 kHz sampling rate feedback systems for final energy stabilization, and (4) continuous beam energy spread monitoring with optical transition radiation devices. We present measurement results showing that small energy spreads are achieved over extended periods.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 769168
- Report Number(s):
- JLAB-ACP-00-05; physics/0009087; DOE/ER/40150-1777; TRN: US0100381
- Resource Relation:
- Conference: Linac 2000, Monterey, CA (US), 08/21/2000--08/25/2000; Other Information: PBD: 1 Aug 2000
- Country of Publication:
- United States
- Language:
- English
Similar Records
Operating experience at CEBAF
Injection, Positron and Electron Beam Generation